Herbicides are widely used by farmers and commercial agricultural companies in order to increase crop yields for such staple crops as corn, soybeans, rice and the like.
Herbicides are effective in killing or controlling weeds and grasses which compete for soil nutrients with the crop plants. One particularly successful herbicide is RO-NEET.RTM., a herbicide of the thiocarbamate type, which is used for the control of weeds in pre-plant sugarbeets, spinach and table beets, particularly. The thiocarbamates are used extensively at the present time.
Not all weeds germinate at the same time or at the same rate. Accordingly, a specific herbicide which may be effective against weeds which germinate at or about the same time as the crop plant, may not be quite as effective against late-germinating weeds. The residual activity of the herbicide against late-germinating weeds leaves something to be desired. One such late-germinating weed is wild proso millet, which is conventionally found in the environment of corn and soybean crop plants.
It would be advantageous to find a method of extending the residual activity of specific herbicides, and that is what this invention is concerned with.